What’s Vulnerable › Vulnerabilities

CVE-2020-0909: Windows Hyper-V Denial of Service Vulnerability

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 4.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-05-21 · updated 2026-08-19

Description

A denial of service vulnerability exists when Hyper-V on a Windows Server fails to properly handle specially crafted network packets. To exploit the vulnerability, an attacker would send specially crafted network packets to the Hyper-V Server. The security update addresses the vulnerability by resolving the conditions where Hyper-V would fail to properly handle these network packets.

Affected products

• Microsoft Windows 10 Version 1607: 1607, 1709, 1803, 1809, 1903, 1909
• Microsoft Windows 7: all versions
• Microsoft Windows 8.1: all versions
• Microsoft Windows Server 2008: r2-sp1
• Microsoft Windows Server 2012: r2
• Microsoft Windows Server 2016: 1803, 1903, 1909
• Microsoft Windows Server 2019: all versions
• Microsoft Windows 10 Version 1507: from 10.0.10240.0 before publication — fixed in publication
• Microsoft Windows 10 1607: from 10.0.14393.0 before publication — fixed in publication
• Microsoft Windows 10 1709: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 1803: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10: from 10.0.17763.0 before publication — fixed in publication
• Microsoft Windows 10 Version 1903 for x64-based Systems: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 1909: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 7 Service Pack 1: from 6.1.0 before publication — fixed in publication
• Microsoft Windows 8.1: from 6.3.0 before publication — fixed in publication
• Microsoft Windows Server 2008 R2 Service Pack 1: from 6.1.7601.0 before publication — fixed in publication
• Microsoft Windows Server 2008 Service Pack 2: from 6.0.6003.0 before publication — fixed in publication
• Microsoft Windows Server 2012: from 6.2.9200.0 before publication — fixed in publication
• Microsoft Windows Server 2012 R2: from 6.3.9600.0 before publication — fixed in publication
• Microsoft Windows Server 2016: from 10.0.14393.0 before publication — fixed in publication
• Microsoft Windows Server 2019: from 10.0.17763.0 before publication — fixed in publication
• Microsoft Windows Server, version 1803 (Server Core Installation): from 10.0.0 before publication — fixed in publication
• Microsoft Windows Server, version 1903 (Server Core installation): from 10.0.0 before publication — fixed in publication
• Microsoft Windows Server, version 1909 (Server Core installation): from 10.0.0 before publication — fixed in publication

How to fix

Upgrade to a fixed version: Microsoft Windows 10 Version 1507 publication; Microsoft Windows 10 1607 publication; Microsoft Windows 10 1709 publication; Microsoft Windows 10 1803 publication; Microsoft Windows 10 publication; Microsoft Windows 10 Version 1903 for x64-based Systems publication; Microsoft Windows 10 1909 publication; Microsoft Windows 7 Service Pack 1 publication; Microsoft Windows 8.1 publication; Microsoft Windows Server 2008 R2 Service Pack 1 publication; Microsoft Windows Server 2008 Service Pack 2 publication; Microsoft Windows Server 2012 publication. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-0909
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-0909

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